1. Field of the Invention
The invention relates to semiconductor technology and more particularly to metal-insulator-metal capacitors.
2. Description of the Related Art
Capacitors are elements used extensively in semiconductor devices for storing an electrical charge or parallel connection with an inductor to be an LC oscillator for signal radiation. Capacitors essentially comprise two conductive plates separated by a dielectric material, and are also used in filters, analog-to-digital converters, memory devices, control applications, and many other types of semiconductor devices.
One type of capacitor is a metal-insulator-metal (MIM) capacitor, which is frequently used in mixed signal devices and logic devices, such as embedded memories and radio frequency devices. Metal-insulator-metal capacitors are used to store a charge in a variety of semiconductor devices. A metal-insulator-metal capacitor is typically formed horizontally on a semiconductor wafer, with two metal plates sandwiching a dielectric layer parallel to the wafer surface. In the radio frequency device applications, tantalum nitride films are often utilized as the metal plates of the metal-insulator-metal capacitors.
The resistivity of a tantalum nitride is typically between 150 and 250 μΩ-cm. In some cases, the value is too high for an integral of a semiconductor device. Thus, a technology for lowering the resistivity of plates of metal-insulator-metal capacitors is desirable.